1. Field of the Invention
This invention relates generally to a corona discharge ignition system, and more particularly to a system and method for supplying energy to a plurality of corona igniters of the corona discharge ignition system.
2. Related Art
Corona discharge ignition systems provide an alternating voltage and current, reversing high and low potential electrodes in rapid succession which enhances the formation of corona discharge and minimizes the opportunity for arc formation. The system typically includes a transformer receiving energy from a power supply in the form of a direct current, amplifying the voltage, and reducing the current prior to directing the energy in the form of an alternating current toward a central electrode of the corona igniter. The central electrode is charged to a high radio frequency voltage potential and creates a strong radio frequency electric field in a combustion chamber. The electric field causes a portion of a mixture of fuel and air in the combustion chamber to ionize and begin dielectric breakdown, facilitating combustion of the fuel-air mixture, which is referred to as an ignition event. The electric field is preferably controlled so that the fuel-air mixture maintains dielectric properties and corona discharge occurs, also referred to as non-thermal plasma. The ionized portion of the fuel-air mixture forms a flame front which then becomes self-sustaining and combusts the remaining portion of the fuel-air mixture. Preferably, the electric field is controlled so that the fuel-air mixture does not lose all dielectric properties, which would create thermal plasma and an electric arc between the electrode and grounded cylinder walls, piston, metal shell, or other portion of the igniter. An example of a corona discharge ignition system is disclosed in U.S. Pat. No. 6,883,507 to Freen.
Oftentimes, the corona discharge ignition system includes a plurality of corona igniters, such as one in each cylinder of the engine. Thus, the system also includes a plurality of energy transformers each ultimately connected to one of the corona igniters. However, use of this design is limited as each transformer is expensive and increases the size and complexity of the corona discharge ignition system.